public function testAdd()
{
$a = 1234;
$b = '1234123412341234123412341234123412412341234213412421341342342';
$c = '0x1234123412341234123412341234123412412341234213412421341342342';
$math = new BcEngine();
$this->assertEquals('2468', $math->add($a, $a));
$this->assertEquals('2468246824682468246824682468246824824682468426824842682684684', $math->add($b, $b));
$this->assertEquals('4020328592351456034599241982311497811554079037632048678982517743814198916', $math->add($c, $c));
$this->assertEquals(2, $math->add(1, 1));
}